CFF-FIT Rubber Hex Dumbbells feature durability that simply can't be matched. It resists cracking and fading while protecting floors and equipment. Made from solid cast iron with a 6-sided anti-roll design and encased in rubber, this dumbbell is stylish as it is durable. Heads are securely fastened with a uniquely designed pin mechanism that means this equipment is about as low-maintenance as it gets. No spinning or loosening. The ergonomic handle (28mm to 34mm) fits nicely in your hands with a soft knurling for grip. Each handle is about 5.875" long. (The 5-Pound handles are 23mm to 28mm and 5.25" between heads.)Warranty: CFF offers a lifetime warranty on the structural integrity and that the heads will not detach from the bar under normal wear and tear.